In the past the greatest difficulty encountered in imparting continuous repeating designs along the lengths of metal rods as they emerge from an extruder has arisen from the relatively soft condition of the metal in combination with the various forces to which they are subjected in emerging from the extruder and being formed.
Extrudable metals such as aluminum and aluminum alloys are often used in the manufacturing of metal furniture, particularly for outdoor use as well as for a wide variety of other uses. Rods of this nature are formed to simulate wrought iron, bamboo, etc., and when properly painted it is often difficult to determine which is the "real thing" and which is a simulation without making a close inspection.
The metal rods emerge from the extruder for forming at a temperature generally in the range of 800.degree. to 900.degree. F. Consequently, they are quite soft and easily deformable. The extruding P.S.I. is manually controllable but generally only within certain ranges. For example, the P.S.I. in a single manual setting may fluctuate between 6 and 12 P.S.I. When a pair of forming rollers are securely positioned relative to the extruder to receive the extrusion for the forming operation and the extrusion P.S.I. fluctuates to the above mentioned degree, the extrusion generally becomes deformed, either buckling or stretching out.
The present invention provides means to compensate for or to counter the P.S.I. fluctuations which results in the elimination of the waste encountered with the presently used forming devices.
Therefore, one of the principal objects of the present invention is to provide the forming rollers and their variable speed drive motor on a trolley carriage, engaged on tracks, for movement toward and away from the extruder with the forming rollers always disposed in engaged alignment with the emerging metal extrusion.
Another principal object of the present invention is to provide means such as a pneumatic piston and cylinder assembly connecting between a fixed position and the trolley carriage to exert a constant predetermined P.S.I. against the carriage trolley in the same direction as the extrusion forces.
A further object of the present invention is to operate the forming roller drive motor at a predetermined R.P.M. to counter the combined P.S.I. of the extrusion and the pneumatic piston and cylinder assembly whereby the carriage trolley drifts forwardly and backwardly in response to the fluctuating P.S.I. of the extrusion, thereby eliminating the buckling and/or stretching deformations resulting from the operation of forming rollers in a fixed position.